Blending of non-absorbable fibers having distinctly different individual physicochemical properties is a well-established practice in the textile industry and is directed toward achieving unique properties based on the constituent fibers in such blends. The most commonly acknowledged examples of these blends include combinations of (1) wool staple yarn and polyethylene terephthalate (PET) continuous multifilament yarn to produce textile fabrics which benefit from the insulating quality of wool and high tensile strength of the polyester; (2) cotton staple yarn and PET continuous multifilament yarn to produce water-absorbing, comfortable (due to cotton), strong (due to PET) fabrics; (3) nylon continuous multifilament yarn and cotton staple yarn to achieve strength and hydrophilicity; and (4) cotton staple yarn and polyurethane continuous monofilament yarn to yield water-absorbing, comfortable elastic fabrics. The concept of blending non-absorbable and absorbable fibers was addressed to a very limited extent in the prior art relative to combining polypropylene (PP) with an absorbable polyester fiber in a few fibrous constructs, such as hernial meshes, to permit tissue ingrowth in the PP component of these meshes and reducing long-term implant mass, as the absorbable fibers lose mass with time. However, the use of totally absorbable/biodegradable blends of two or more yarns to yield fibrous properties that combine those of the constituent yarns is heretofore unknown in the prior art. This provided the incentive to pursue this invention, which deals with totally absorbable/biodegradable composite yarns having at least two fibrous components and their conversion to medical devices, such as sutures and meshes, with modulated, integrated physicochemical and biological properties derived from the constituent yarns and which can be further modified to exhibit specific clinically desired properties.
A key feature of having an absorbable/biodegradable surgical implant comprising at least two differing fibrous components, which, in turn exhibit different absorption and strength retention profiles has been disclosed in the present parent application PCT Serial No. 2006014939. However, these applications did not describe any specifically new construct design of devices such as surgical sutures and hernial meshes, which are responsible for achieving novel clinical properties. Accordingly, this invention is directed to novel construct designs made of fully absorbable/biodegradable surgical sutures, especially those used in slow-healing tissues and surgical meshes such as those used in hernial repair and vaginal tissue reconstruction.